Guarantor And Non-Guarantor Consolidating Condensed Financial Statements (Consolidating Condensed Statements Of Comprehensive Income) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues
Revenues	$ 2,753	$ 2,778	$ 7,010	$ 7,074
Expenses
Operating	1,291	1,294	3,534	3,561
Vehicle depreciation and lease charges, net	551	587	1,579	1,693
Selling, general and administrative	350	336	947	953
Vehicle interest, net	90	85	261	237
Non-vehicle related depreciation and amortization	62	62	195	190
Interest expense	49	44	139	139
Intercompany interest expense (income)	0	0	0	0
Early extinguishment of debt	10	0	10	5
Restructuring and other related charges	22	4	66	14
Transaction-related costs, net	0	11	6	18
Total expenses	2,425	2,423	6,737	6,810
Income (loss) before income taxes and equity in earnings of subsidiaries	328	355	273	264
Provision for (benefit from) income taxes	(139)	(142)	(113)	(112)
Equity in earnings of subsidiaries	0	0	0	0
Net income	189	213	160	152
Comprehensive income	155	207	119	104
Eliminations [Member]
Revenues
Revenues	(598)	(560)	(1,816)	(1,792)
Expenses
Operating	0	0	0	0
Vehicle depreciation and lease charges, net	(528)	(504)	(1,611)	(1,625)
Selling, general and administrative	0	0	0	0
Vehicle interest, net	(70)	(56)	(205)	(167)
Non-vehicle related depreciation and amortization	0	0	0	0
Interest expense	0	0	0	0
Intercompany interest expense (income)	0	0	0	0
Early extinguishment of debt	0		0
Restructuring and other related charges	0	0	0	0
Transaction-related costs, net	0	0	0	0
Total expenses	(598)	(560)	(1,816)	(1,792)
Income (loss) before income taxes and equity in earnings of subsidiaries	0	0	0	0
Provision for (benefit from) income taxes	0	0	0	0
Equity in earnings of subsidiaries	(717)	(812)	(1,224)	(1,179)
Net income	(717)	(812)	(1,224)	(1,179)
Comprehensive income	(624)	(794)	(1,147)	(1,016)
Parent Company [Member]
Revenues
Revenues	0	0	0	0
Expenses
Operating	1	0	2	2
Vehicle depreciation and lease charges, net	0	0	0	0
Selling, general and administrative	14	10	35	38
Vehicle interest, net	0	0	0	0
Non-vehicle related depreciation and amortization	0	0	0	0
Interest expense	0	0	0	0
Intercompany interest expense (income)	(3)	(3)	(9)	(9)
Early extinguishment of debt	0		0
Restructuring and other related charges	4	0	15	0
Transaction-related costs, net	0	0	0	0
Total expenses	16	7	43	31
Income (loss) before income taxes and equity in earnings of subsidiaries	(16)	(7)	(43)	(31)
Provision for (benefit from) income taxes	5	2	15	13
Equity in earnings of subsidiaries	200	218	188	170
Net income	189	213	160	152
Comprehensive income	155	207	119	104
Subsidiaries [Member]
Revenues
Revenues	0	0	0	0
Expenses
Operating	1	3	1	4
Vehicle depreciation and lease charges, net	0	0	0	0
Selling, general and administrative	5	3	13	9
Vehicle interest, net	1	0	1	0
Non-vehicle related depreciation and amortization	1	0	6	1
Interest expense	36	37	104	115
Intercompany interest expense (income)	(34)	1	(26)	(8)
Early extinguishment of debt	10		10	5
Restructuring and other related charges	0	0	0	0
Transaction-related costs, net	2	0	3	1
Total expenses	22	44	112	127
Income (loss) before income taxes and equity in earnings of subsidiaries	(22)	(44)	(112)	(127)
Provision for (benefit from) income taxes	8	12	40	34
Equity in earnings of subsidiaries	214	250	260	263
Net income	200	218	188	170
Comprehensive income	166	212	147	122
Guarantor Subsidiaries [Member]
Revenues
Revenues	1,606	1,592	4,236	4,171
Expenses
Operating	755	737	2,089	2,035
Vehicle depreciation and lease charges, net	553	540	1,679	1,681
Selling, general and administrative	195	182	526	513
Vehicle interest, net	70	59	205	172
Non-vehicle related depreciation and amortization	37	36	110	108
Interest expense	1	0	2	2
Intercompany interest expense (income)	6	9	20	20
Early extinguishment of debt	0		0
Restructuring and other related charges	8	2	33	6
Transaction-related costs, net	0	2	(6)	3
Total expenses	1,625	1,567	4,658	4,540
Income (loss) before income taxes and equity in earnings of subsidiaries	(19)	25	(422)	(369)
Provision for (benefit from) income taxes	(70)	(119)	(94)	(114)
Equity in earnings of subsidiaries	303	344	776	746
Net income	214	250	260	263
Comprehensive income	185	244	243	207
Non-Guarantor Subsidiaries [Member]
Revenues
Revenues	1,745	1,746	4,590	4,695
Expenses
Operating	534	554	1,442	1,520
Vehicle depreciation and lease charges, net	526	551	1,511	1,637
Selling, general and administrative	136	141	373	393
Vehicle interest, net	89	82	260	232
Non-vehicle related depreciation and amortization	24	26	79	81
Interest expense	12	7	33	22
Intercompany interest expense (income)	31	(7)	15	(3)
Early extinguishment of debt	0		0
Restructuring and other related charges	10	2	18	8
Transaction-related costs, net	(2)	9	9	14
Total expenses	1,360	1,365	3,740	3,904
Income (loss) before income taxes and equity in earnings of subsidiaries	385	381	850	791
Provision for (benefit from) income taxes	(82)	(37)	(74)	(45)
Equity in earnings of subsidiaries	0	0	0	0
Net income	303	344	776	746
Comprehensive income	$ 273	$ 338	$ 757	$ 687